Until last week, I was under the impression that the human brain was not producing new neurons after a certain age. Anyone else under this impression? Luckily we’re all wrong! This post quickly brings you one step closer to stimulating those new neurons.
Neuroscientist Sandrine Thuret asked the question,“can we as adults grow new nerve cells?” The answer is yes. It’s a new field of research but we do know a few concrete pieces of evidence.
When a colleague of Sandrine Thuret, an oncologist, was puzzled by why some of his cured cancer patients still had symptoms of depression, often even after taking antidepressants. Thuret reasoned that the drugs that stopped the cancer cells from multiplying, “also stops newborn neurons from being generated in the brain (2015).” This question ultimately established a clear link between depression and neurogenesis. In an animal model, it was revealed that “if you block neurogenesis, then you block the efficacy of the antidepressant (Thuret, 2015).” From this, Thuret’s colleague reasoned that “his patients were suffering from depression even after being cured of their cancer, because the cancer drug had stopped newborn neurons from being generated. And it will take time to generate new neurons that reach normal functions (2015).”
At this point in time, researchers have been able to see that neurogenesis occurs in the hippocampus, meaning new neurons can be generated here! The hippocampus regulates human learning, memory, mood, and emotion.
“Jonas Frisén from the Karolinska Institutet, has estimated that we produce 700 new neurons per day in the hippocampus… we will have all exchanged the neurons we were born with in that structure with adult-born neurons.So why are these new neurons important and what are their functions? First, we know that they're important for learning and memory. And in the lab we have shown that if we block the ability of the adult brain to produce new neurons in the hippocampus, then we block certain memory abilities. And this is especially new and true for spatial recognition -- like, how you navigate your way in the city. Not only important for memory capacity, but also for the quality of the memory, like: how do you find your bike that you park at the station every day in the same area, but in a slightly different position? (Thuret, 2015).”
Thuret and other researchers collectively believe that “that neurogenesis is a target of choice if we want to improve memory formation or mood, or even prevent the decline associated with aging, or associated with stress (2015).”
So,can we control neurogenesis? Yes! Lucky for us there are specific activities and diets that can increase neurogenesis.
Will learning increase neurogenesis? Yes!
Stress and sleep deprivation? No! In fact these two things will decrease neurogenesis.
Getting older? Not necessarily. The rate of neurogenesis will decrease but is still occurring.
The environment? Yes!
Running? Definitely yes!
“One of the first studies that was carried out by one of my mentors, Rusty Gage from the Salk Institute, showing that the environment can have an impact on the production of new neurons. And here you see a section of the hippocampus of a mouse that had no running wheel in its cage. And the little black dots you see are actually newborn neurons-to-be. And now, you see a section of the hippocampus of a mouse that had a running wheel in its cage. So you see the massive increase of the black dots representing the new neurons-to-be (2015).”
What type of diets will increase neurogenesis? Researchers have found several, the first beingrestricting calorie intake by 20-30% and second,intermittent fasting, which is spacing the amount of time between you meals. The third and fourth suggestions areincreased intake of flavonoids (which can be found in dark chocolate and blueberries, score!)and Omega-3 fatty acids, in fish like salmon. Alternatively, diets rich in high saturated fat and alcohol will decrease neurogenesis. Not all is lost though,consumption of red wine has been shown to promote the survival of new neurons because it contains resveratrol.
Last quirky element that could impact neurogenesis? Food texture!
“Japanese groups are fascinated with food textures, and they have shown that actually soft diet impairs neurogenesis, as opposed to food that requires mastication -- chewing -- or crunchy food (Thuret, 2015).”
It’s clear that we’ve only grazed the surface level of neurogenesis but Thuret provided us several tools to start applying to our own lives.
Thanks for reading!
Thuret, S. (2015, June). Sandrine Thuret: You can grow new brain cells. Here’s how [Video file]. Retrieved from https://www.ted.com/talks/sandrine_thuret_you_can_grow_new_brain_cells_here_s_how?utm_campaign=tedspread&utm_medium=referral&utm_source=tedcomshare#t-259929
Photo credit: Ali Brown (@queenboomkitty)
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